#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>

int main()
{
	//int a = 10;
	//int* p1 = &a;
	//*p1 = 20;

	int* p2 = NULL;
	if (p2 != NULL)
	{
		
	}
	//*p2 = 100;//err


	return 0;
}
